In later life, the hyperactive/impulsive subtype manifests less frequently.[1](p44) The hyperactivity symptoms tend to turn more into "inner restlessness", starting in adolescence and carrying on in adulthood.[3]

Adult ADHD is typically marked by inattentiveness, difficulty getting work done, procrastination and organizational problems. Specifically, adults with ADHD present with persistent difficulties in following directions, remembering information, concentrating, organizing tasks, completing work within specified time frames and appearing timely in appointments. These difficulties affect several different areas of an ADHD adult's life, causing emotional, social, vocational, marital, legal, financial and/or academic problems.[4][5][6] As a result, low self-esteem is commonly developed. However, given the right guidance and coaching, these traits of ADHD could also lead to career success, and in some cases, unique advantages in critical thinking and creativity.[7]

Diagnosis of the condition follows after one or several assessment interviews by a clinician including:

The condition is highly heritable,[10] and while its exact causes are not fully known, genetic or environmental factors are understood to play a part. ADHD is a childhood-onset condition, usually requiring symptoms to have been present before age 12 for a diagnosis.[11] Children under treatment will migrate to adult health services if necessary as they transit into adulthood, however diagnosis of adults involves full examination of their history.

at least six hyperactive-type symptoms for the hyperactive-impulsive type

all of the above to have the combined type

The symptoms (see below) were required to have been present since before the individual was seven years old, and must have interfered with at least two spheres of his or her functioning (at home and at school or work, for example) over the last six months.[14] The DSM-IV criteria for ADHD were, however, tailored towards the type of symptoms that children would show, and might therefore have underestimated the prevalence of ADHD in adults.[1][page needed] In 2013, the newer DSM-5 reviewed some of these criteria, with more lenient requirements for the diagnosis, especially in adults, and the age limit for symptoms first arising raised to twelve years.[15]

ADHD is a chronic condition, beginning in early childhood and persisting throughout a person's lifetime. It is estimated that 33–66% of children with ADHD will continue to have significant ADHD-related symptoms persisting into adulthood, resulting in a significant impact on education, employment, and interpersonal relationships.[6][16]

Individuals with ADHD exhibit deficiencies in self-regulation and self-motivation which in turn foster problematic characteristics such as distractibility, procrastination and disorganization. They are often perceived by others as chaotic, with a tendency to need high stimulation to be less distracted and function effectively. The learning potential and overall intelligence of an adult with ADHD, however, are no different from the potential and intelligence of adults who do not have the disorder.

Whereas teachers and caregivers responsible for children are often attuned to the symptoms of ADHD, employers and others who interact with adults are less likely to regard such behaviors as a symptom. In part, this is because symptoms do change with maturity; adults who have ADHD are less likely to exhibit obvious hyperactive behaviors. Instead, they may report constant mental activity and inner restlessness as their hyperactivity internalizes.[3]

The difficulties generated by these deficiencies can range from moderate to extreme, resulting in the inability to effectively structure their lives, plan daily tasks, or think of and act accordingly even when aware of potential consequences. These lead to poor performance in school and work, followed by underachievement in these areas. In young adults, poor driving record with traffic violations[17] as well as histories of alcoholism or substance abuse may surface. The difficulty is often due to the ADHD person's observed behaviour (e.g. the impulsive types, who may insult their boss for instance, resulting in dismissal), despite genuinely trying to avoid these and knowing that it can get them in trouble. Often, the ADHD person will miss things that an adult of similar age and experience should catch onto or know. These lapses can lead others to label the individuals with ADHD as "lazy" or "stupid" or "inconsiderate".

Studies on adults with ADHD have shown that, more than often, they experience self stigma and depression in childhood, commonly resulting from feeling neglected and different from their peers.[20] These problems may play a role to the high levels of depression, substance abuse, and relationship problems that affect adults with ADHD later in life.[21]

Inattentive-type (ADHD-PI)

Hyperactive/Impulsive-type (ADHD-PH)

In children:

Forgetful during daily activities

Easily distracted by extraneous stimuli

Losing important items (e.g. pencils, homework, toys, etc.)

Always asking for attention, but

Not listening and not responding to name being called out

Unable to focus on tasks at hand, cannot sustain attention in activities

Over the last 30 years, research into ADHD has greatly increased.[22] There is no single, unified theory that explains the cause of ADHD. Genetic factors are presumed important, and it has been suggested that environmental factors may affect how symptoms manifest.[3][23]

It is becoming increasingly accepted that individuals with ADHD have difficulty with "executive functioning". In higher organisms, such as humans, these functions are thought to reside in the frontal lobes. They enable recall of tasks that need accomplishing, organization to accomplish these tasks, assessment of consequences of actions, prioritization of thoughts and actions, keeping track of time, awareness of interactions with surroundings, the ability to focus despite competing stimuli, and adaptation to changing situations.

The diagnosis of ADHD in adults requires retrospectively establishing whether the symptoms were also present in childhood, even if not previously recognized. As with other mental disorders such as schizophrenia there is no objective "test" that diagnoses ADHD.[29][30] Rather, it is a combination of a careful history of symptoms up to early childhood, including corroborating evidence from family members, previous report cards, etc. The screening tests also seek to rule out other conditions or differential diagnoses such as depression, anxiety, or substance abuse. Other diseases such as hyperthyroidism may exhibit symptoms similar to those of ADHD, and it is imperative to rule these out as well. Asperger syndrome, a condition on the autism spectrum, is sometimes mistaken for ADHD, due to impairments in executive functioning found in some people with Asperger syndrome. However, Asperger syndrome also typically involves difficulties in social interaction, restricted and repetitive patterns of behavior and interests, and problems with sensory processing, including hypersensitivity. Along with this, the quality of diagnosing an adult with ADHD can often be skewed being that the majority of adults with ADHD also have other complications, ranging from anxiety and depression to substance abuse.[21]

Assessment of adult patients seeking a possible diagnosis can be better than in children due to the adult's greater ability to provide their own history, input, and insight. However, it has been noted that many individuals, particularly those with high intelligence, develop coping strategies that mask ADHD impairments and therefore they do not seek diagnosis and treatment.[31][unreliable medical source?]

Formal tests and assessment instruments such as IQ tests, standardized achievement tests, or neuropsychological tests typically are not helpful for identifying people with ADHD.[9] Furthermore, no currently available physiological or medical measure is definitive diagnostically. However, psycho-educational and medical tests are helpful in ruling in or out other conditions (e.g. learning disabilities, mental retardation, allergies) that may be associated with ADHD-like behaviors.

United States medical and mental health professionals follow the Diagnostic and Statistical Manual of Mental Disorders (DSM) of the American Psychiatric Association; the International Classification of Diseases (ICD) published by the World Health Organisation (WHO) is often used by health professionals elsewhere. Periodic updates incorporate changes in knowledge and treatments.[32][unreliable medical source] For example, under DSM-IV (published in 1994, with corrections and minor changes in 2000), the diagnostic criteria for ADHD in adults broadly follow the same as in children,[33] but the proposed revision for the DSM-5 differentiates the presentation of ADHD for children and adults for several symptoms.[34]

It should be noted that every normal individual exhibits ADHD-like symptoms occasionally (when tired or stressed, for example) but for a positive diagnosis to be received, the symptoms should be present from childhood and persistently interfere with functioning in multiple spheres of an individual's life: work, school, and interpersonal relationships. The symptoms that individuals exhibit as children are still present in adulthood, but manifest differently as most adults develop compensatory mechanisms to adapt to their environment.

Treatment for adult ADHD may combine medication and behavioral, cognitive, or vocational interventions.[35] Treatment often begins with medication selected to address the symptoms of ADHD, along with any comorbid conditions that may be present. Medication alone, while effective in correcting the physiological symptoms of ADHD, will not address the paucity of skills which many adults will have failed to acquire because of their ADHD (e.g., one might regain ability to focus with medication, but skills such as organizing, prioritizing and effectively communicating have taken others time to cultivate).[36]

Stimulants, the first line medications in adult ADHD, are typically formulated in immediate and long-acting formulations.

Methylphenidate, a stimulant, with short and long-acting formulations, is often the first-line therapy and appears effective.[37] In the short term, methylphenidate is well tolerated. However, long term studies have not been conducted in adults and concerns about increases in blood pressure have not been established.[38] Methylphenidate increases concentrations of dopamine and norepinephrine in the synaptic cleft, promoting increased neurotransmission. It acts to block the dopamine and norepinephrine reuptake transporters, thus slowing the removal at which these neurotransmitters are cleared from the synapses.

Amphetamine and its derivatives, prototype stimulants, are likewise available in immediate and long-acting formulations. Amphetamines act by multiple mechanisms including reuptake inhibition, displacement of transmitters from vesicles, reversal of uptake transporters and reversible MAO inhibition. Thus amphetamines actively increases the release of these neurotransmitters into the synaptic cleft.[39] They may have a better side-effect profile than methylphenidate cardiovascularly and potentially better tolerated.[40]

The non-stimulant atomoxetine (Strattera), is also an effective treatment for adult ADHD. Although atomoxetine has a half life similar to stimulants it exhibits delayed onset of therapeutic effects similar to antidepressants. Unlike the stimulants which are controlled substances, atomoxetine lacks abuse potential. It is particularly effective for those with the predominantly inattentive concentration type of attention deficit due to being primarily a norepinephrine reuptake inhibitor.[41] It is often prescribed in adults who cannot tolerate the side effects of amphetamines or methylphenidate. It is also approved for ADHD by the US Food and Drug Administration. A rare but potentially severe side effect includes liver damage and increased suicidal ideation.[42]

For most adults, the psychosocial therapy is not effective.[citation needed] For this reason, medications are the first line of therapies. The medications that are prescribed for adults come in both stimulant and non-stimulant form. Although the drug therapies are effective for adults, the benefits should be discussed with the patient’s physician to ensure the benefits of the medications outweigh the risk. If medication is unwanted or not an option, increasing exercise and changing one’s diet may help alleviate some of the symptoms such as hyperactivity[47]

Exercise may alleviate some of the symptoms of ADHD for approximately 45 minutes.[citation needed]

In North America and Europe, it is estimated that three to five percent of adults have ADHD, but only about ten percent of those have received a formal diagnosis.[48][non-primary source needed][49][non-primary source needed] It has been estimated that 5% of the global population has ADHD (including cases not yet diagnosed).[50][51] In the context of the World Health Organization World Mental Health Survey Initiative, researchers screened more than 11,000 people aged 18 to 44 years in ten countries in the Americas, Europe and the Middle East. On this basis they estimated the adult ADHD proportion of the population to average 3.5 percent with a range of 1.2 to 7.3 percent, with a significantly lower prevalence in low-income countries (1.9%) compared to high-income countries (4.2%). The researchers concluded that adult ADHD often co-occurs with other disorders, and that it is associated with considerable role disability. Although they found that few adults are treated for ADHD itself, in many instances treatment is given for the co-occurring disorders.[52][non-primary source needed]

Early work on disorders of attention was conducted by Alexander Crichton in 1798 writing about "mental restlessness".[53] The underlying condition came to be recognized from the early 1900s by Sir George Still.[54][55] Efficacy of medications on symptoms was discovered during the 1930s and research continued throughout the twentieth century. ADHD in adults began to be studied from the early 1970s and research has increased as worldwide interest in the condition has grown.

In the 1970s researchers began to realize that the condition now known as ADHD did not always disappear in adolescence, as was once thought.[22] The expansion of the definition for ADHD beyond only being a condition experienced by children was mainly accomplished by refocusing the diagnosis on inattention instead of hyperactivity.[56] At about the same time, some of the symptoms were also noted in many parents of the children under treatment.[citation needed] The condition was formally recognized as affecting adults in 1978, often informally called adult ADD, since symptoms associated with hyperactivity are generally less pronounced.[57][unreliable medical source]

ADHD in adults, as with children, is recognized as an impairment that may constitute a disability under U.S. federal disability nondiscrimination laws, including such laws as the Rehabilitation Act of 1973 and the Americans With Disabilities Act (ADA, 2008 revision), if the disorder substantially limits one or more of an individual's major life activities. For adults whose ADHD does constitute a disability, workplaces have a duty to provide reasonable accommodations, and educational institutions have a duty to provide appropriate academic adjustments or modifications, to help the individual work more efficiently and productively.[58][59]

In a 2004 study it was estimated that the yearly income discrepancy for adults with ADHD was $10,791 less per year than high school graduate counterparts and $4,334 lower for college graduate counterparts. The study estimates a total loss in productivity in the United States of over $77 billion USD.[60][unreliable medical source] By contrast, loss estimations are $58 billion for drug abuse, $85 billion for alcohol abuse and $43 billion for depression.[61][unreliable medical source]

ADHD controversies include concerns about its existence as a disorder, its causes, the methods by which ADHD is diagnosed and treated including the use of stimulant medications in children, possible overdiagnosis, misdiagnosis as ADHD leading to undertreatment of the real underlying disease, alleged hegemonic practices of the American Psychiatric Association and negative stereotypes of children diagnosed with ADHD. These controversies have surrounded the subject since at least the 1970s.[54][62]

^Eden, GF; Vaidya, CJ (2008). "ADHD and developmental dyslexia: two pathways leading to impaired learning". Annals of the New York Academy of Sciences. 1145: 316–27. doi:10.1196/annals.1416.022. PMID19076406.

^Moon, Kathryn F. (2004). "Development of the DSM". The History of Psychiatric Classification: From Ancient Egypt to Modern America (A Website composed for the History of Psychology (PSYC 6180) The University of Georgia). Archived from the original on 6 June 2009.